More Harmful Effects of Smoking Weed While Breastfeeding. More medical studies need to be done to determine marijuanaâs effects on breast milk, but below are some of the areas studies have indicated contain risk factors.urthermore, marijuana use can diminish the abilities of a mother to take care of her newborn. The American Academy of Pediatrics advises nursing mothers not to use marijuana while breastfeeding. However, in some states medical marijuana is used to treat anxiety and other medical conditions.
We can see fossils of many other reptiles in rock of the same age and even older, but Archaeopteryx lithographica is the oldest known fossil to have feathers. We conclude that this animal is a link between reptiles and birds and that birds are descended from reptiles.ossils can be used to recognize rocks of the same or different ages. The fossils in this figure are the remains of microscopic algae. The pictures shown were made with a scanning electron microscope and have been magnified about 250 times.
You can learn more about the process in How Earthquakes Work. Environmental effects, like weathering and erosion, can also reveal very old layers of sedimentary rock. This is a very simplified view of the process, but it demonstrates two key points that are necessary to understanding fossils.One is that sedimentary rock forms the surface of the Earth.The other is that the Earth's movement has a big impact on how and where these rocks appear.f you've read How the Earth Works, you know that the Earth's physical structure has several distinct layers. There's a solid inner core, a molten outer core, a malleable mantle and a solid crust. The crust, the thinnest layer, forms the Earth's surface, and it's where fossils are both formed and found.